Resilient sole and method for manufacturing same

ABSTRACT

Resilient sole 1 which is attached to a concrete layer (2) or which is positioned between a concrete layer (2) and ballast (3), and which is formed by a layer (4) of recycled rubber, in the revulcanised state after devulcanisation, and a layer (5) of structured fibres which is arranged so as to be in contact with the rubber layer, the fibres being partially impregnated in the rubber layer and having a free thickness (8) of structured fibres, assembly comprising the sole and method for manufacturing same.

The present invention relates to a resilient sole arranged to beattached to a concrete layer or which is positioned between a concretelayer and a ballast, as well as a method for manufacturing such aresilient sole.

The present invention also relates to an assembly comprising a concretelayer and a resilient sole such as mentioned above.

Such soles are well known from the state of the art.

In the construction field, such soles are arranged to be attached toconcrete layers or blocks.

In the railway field, such soles are positioned between the rails andthe ballast, the ballast forming the bed of the railway line.

The rail is a treated wood, steel or concrete transverse part, on whichthe rails of a railway line are attached, in order to keep them paralleland to transmit the load that they support to the ballast.

The ballast is formed of crushed stones and is arranged to receive therails on which the railway rails rest.

These types of soles positioned between the ballast and the rails aim todampen the propagation of vibrations generated by the passage of thetrain on the rails to the bed of the underlying railway line andtherefore to the ballast, to avoid wear, as well as the compression ofthe ballast, as well as to avoid wear of the rails and in particular, ofthe concrete rails by the ballast. Indeed, without soles positionedbetween the ballast and the rails, the concrete rails would therefore bein direct contact with the crushed stones of the ballast. This wouldtherefore lead to cracks and a concrete becoming brittle over time.

For example, document FR2935399 describes a resilient sole which isequipped with wires forming stainless steel loops which are buried in anextruded viscoelastic plate with a maximum of 4 loops per cm² ofextruded viscoelastic plate during moulding. These wires are also buriedin the concrete block during the moulding of the latter.

Unfortunately, these wires are easily detached from the viscoelasticplate, wherein they are directly buried, easily deformed or broken dueto the shearing stresses under the effect of the repeated passages ofthe trains on the rails of the railway.

In addition, the wires do not make it possible to obtain a satisfactoryfastening of the concrete to the extruded viscoelastic plate.

Document WO2019201761 describes a sole comprising a resilient layer anda fibre layer which comprises different elements such as grooves,randomly arranged fibres and solidified zones. The solidified zones areobtained by heat treatment or local bonding of fibres.

Unfortunately, the manufacture of this sole requires considerable time.The fibrous layer must be reinforced in certain places, the fibres mustnot be present or barely present in other places of the upper surface ofthe resilient layer and reinforcements of certain places must be done byadding more numerous fibres.

Document WO2012040798 describes a resilient sole comprising arubber-based resilient layer and a groundsheet arranged on the resilientlayer. The groundsheet comprises, on the one hand, a sheet base in theform of an extruded film and, on the other hand, filaments which can bein the form of loops, mushrooms or hooks. The filaments are made ofpolymers and are attached to the extruded film by welding. The resilientlayer and the extruded film are associated with one another by bondingor welding of the base of the groundsheet to the resilient layer.

Unfortunately, first this resilient sole is associated with a specificconcrete, the manufacture of which is explained in the document. Thefilaments are affixed against the concrete milk during the hardening ofthe rails in order to not impact the resistance of the rails. This soleis therefore highly dependent on the quality of the concrete used toform the rail. In addition, this document mentions nothing regarding theresistance of the concrete rails, fibres and resilient layer assembly.However, it is probable that later, the bonding or the welding of theresilient layer to the base of the sheet (extruded film) is a source offragility of the “concrete rails, fibres and resilient layer” assembly.

Document EP129852 describes a resilient sole comprising an extrudedresilient layer and a plastic fibrous layer entangled in the extrudedresilient layer by welding, the fibrous layer being composed of anon-woven geotextile.

Unfortunately, the use of a geotextile-type textile involves asignificant cost for producing these types of resilient soles which arepresent under each rail of the railway line.

It is also probable that later, as for document WO2012040988, thewelding of the resilient layer to the base of the geotextile or of aplastic non-woven fabric is a source of fragility of the “concreterails, fibres and resilient layer” assembly.

In patent application WO2009/108972, a resilient sole to be attached,for example, to concrete rails is disclosed. This sole comprises severalelastomer material layers which are reinforced by a reinforcing layerarranged between two elastomer layers, and which are covered with abonding layer intended for a fastening with the concrete. During themanufacture of the sole, these reinforcing or bonding layers are, onetotally, the other partially, buried in the elastomer layers during theexpansion reaction of these. Such soles are complex to manufacture andassuringly do not enable a manufacture from vulcanised rubber wastewhich is recycled.

The invention aims to overcome the disadvantages of the state of the artby providing a robust resilient sole arranged to confer a“sole-under-sole rail” assembly to resist the stresses exerted by therailway line, from vulcanised rubber waste, and using a simple andeconomic manufacturing method.

To resolve this problem, a resilient sole arranged to be attached to aconcrete layer or positioned between a concrete layer and a ballast isprovided according to the invention, which is formed of a recycledrubber layer, in the revulcanised state after devulcanisation, and alayer of structured fibres, which is arranged so as to be in contactwith the rubber layer, said fibres being partially impregnated in saidrubber layer and having a free thickness of structured fibres.

As can be observed, in the sole according to the present invention, therubber layer of the resilient sole comes from a recycling process andcan comprise production waste, cutting waste or also used waste.

By the term “structured fibres”, this means, according to the invention,fibres entangled in a weft, or fibres arranged on several layers ofsuperposed textile fibres. These fibres can be mixed during themanufacturing process using special hook needles to form a dense andcompact layer of structured fibres which is optionally then coated, inorder to solidify the assembly, like for example felts or carpetsneedled, used frequently for pop-up events (exhibition stand, redcarpet, etc.).

The structured fibres can come from the recycling process. According tothe type of structured fibres, like for example in the case ofproduction waste, it is possible according to the present invention touse directly structured fibres to form said layer of structured fibresof the resilient sole.

The rubber used in the resilient sole according to the present inventionis a recycled rubber, more specifically a rubber which has beendevulcanised. The devulcanised rubber is a rubber which has beendecrosslinkable, i.e. a rubber wherein some of the sulphur bonds havebeen broken.

The rubber is then revulcanised by a hot pressing method. The rubberobtained is therefore a rubber wherein the sulphur bonds are recreatedduring the hot pressing.

According to the present invention, the structured fibres of the layerof structured fibres are partially impregnated in the rubber layer. Thisimpregnation occurs during the hot pressing of the formed layer of thedevulcanised rubber. During hot pressing, the rubber is revulcanised inthe thickness of the rubber layer, but also around structured fibres.

According to the present invention, by the term “partially impregnatedin the rubber layer”, it is understood that the layer of structuredfibres has a free thickness of structured fibres, i.e. non-impregnatedby the revulcanised rubber and a thickness of structured fibresimpregnated in the revulcanised rubber.

Surprisingly, the association of at least one recycled rubber layer andat least one layer of structured fibres impregnated in the revulcanisedrubber makes it possible to obtain a robust resilient sole and resistantto the tearing of the layer of structured fibres which are impregnatedin the revulcanised rubber layer according to the tests in force.

The tests in forced are: standard ISO 37 to measure the resistance totraction, as well as the Shore hardness, standard EN16730 to measure thestatic and dynamic rigidity, the resistance to ageing, the resistance tofatigue and the resistance to tearing.

In addition, when the under-rail sole is associated with a concrete railduring the manufacture of it, the thickness of structured fibresnon-impregnated in the revulcanised rubber layer is thus impregnated inthe concrete before hardening. Once the concrete has hardened, it hasbeen identified also most surprisingly that the assembly has anexcellent resistance to the tearing of the layer of structured fibres ofthe concrete. The layer of impregnated structured fibres is and thusremains integral on the one hand with the rubber, and on the other hand,with the concrete during the tearing tests, which forms a resilient soleresistant to the exerted stresses, like for example those exerted by therailway line and its use. Advantageously, the resistance to tearing ofthe resilient sole according to the invention/rail exceeds 0.8 MPa.

Advantageously, the density of the structured fibres of the resilientsole according to the present invention is between 150 g/m² and 800g/m², preferably between 170 and 750 g/m², advantageously between 190and 500 g/m². Such a density of structured fibres offers the advantageof increasing the resistance to tearing during tests.

Advantageously, the fibres of the resilient sole according to thepresent invention are impregnated at a depth of between 0.5 and 2 mm,preferably between 0.7 and 1.5 mm, preferably between 0.9 and 1 mm insaid revulcanised rubber layer. This has the advantage of creating arevulcanised rubber interphase—robust fibres, and resistant to thestresses exerted by the railway line. The resistance to fibre/rubbertearing advantageously exceeds 1 MPa. This interphase enables the soleto have a resistance to tearing of the concrete block when it ispresent, as well as a resistance to tearing of the rubber layer.

Preferably, said devulcanised-revulcanised recycled rubber layer of theresilient sole according to the present invention has a Shore hardnessof between 50 and 90 Shore A, according to the standard measuring model,the durometer. This has the advantage of obtaining a wide range ofrigidity of the rubber, and therefore to cover the needs of thedifferent actors of the targeted market.

Preferably, said devulcanised-revulcanised recycled rubber layer of theresilient sole according to the present invention has a resistance totraction greater than or equal to 7 MPa, preferably greater than orequal to 8 MPa, advantageously greater than or equal to 9 MPa, even moreadvantageously equal to 10 MPa. This has the advantage that the recycledrubber layer composing the resilient sole resists wear, like for examplewear that the ballast causes following contact between the lower surfaceof the recycled rubber layer and the ballast.

Preferably, said devulcanised-revulcanised recycled rubber layer of theresilient sole according to the present invention has an extension torupture greater than 150%, preferably greater than 200%, even greaterthan 250%. This has the advantage that the recycled rubber layercomposing the resilient sole is resistant to the different forcesundergone by the sole and sufficiently rigid to ensure its role ofdissipator of vibrations that the railway line undergoes.

Preferably, said fibres of the layer of structured fibres of theresilient sole according to the present invention are chosen from thegroup of natural or synthetic materials, like for example polyester,polypropylene, polystyrene, polyethylene, wool, cotton, hemp, coconutfibres.

Advantageously, said rubber layer of the resilient sole according to thepresent invention comprises rubber chosen from the group of natural orsynthetic materials, like for example natural polyisoprene, isoprenepolymer, polybutadiene, styrene-butadiene copolymer.

Other embodiments of the resilient sole according to the invention areindicated in the accompanying claims.

The present invention also relates to an assembly comprising a concretelayer and a resilient sole such as described above, wherein saidstructured fibres are further partially impregnated in said concretelayer, on the free thickness of structured fibres.

Advantageously, the concrete layer can be a concrete block or a mouldedconcrete element, advantageously a railway rail.

In an embodiment of the assembly according to the present invention,said fibres are impregnated in the concrete layer of the assemblyaccording to the present invention on a thickness of between 0.3 and 2mm, preferably between 0.4 and 1.8 mm, more specifically, between 0.5and 1 mm. Advantageously, an impregnation of the fibres on such athickness makes it possible to obtain a resilient sole-integral concretelayer assembly.

Other embodiments of the “concrete layer-resilient sole” assemblyaccording to the invention are indicated in the accompanying claims.

The invention also aims to provide a production method which enables aproduction in an industrial quantity and at a low cost of a quality,robust resilient sole, and resistant to the stresses exerted, forexample, by the regular passage of trains.

According to the invention, this problem is resolved by a method formanufacturing a resilient sole comprising:

-   -   a devulcanisation of recycled rubber, with formation of a        devulcanised recycled rubber mass,    -   an addition of at least one devulcanised recycled rubber        additive,    -   a superposition of a layer of structured fibres and of the        devulcanised recycled rubber with the obtaining of two        superposed layers, and    -   a hot pressing of said two superposed layers at a temperature of        between 100 and 180° C. during a predetermined time interval        with revulcanisation of the devulcanised recycled rubber and        formation of a resilient sole where the structured fibres are at        least partially impregnated in said rubber layer during        revulcanisation by forming a revulcanised rubber-fibre        interphase.

The method for manufacturing a resilient sole according to the presentinvention has the advantage of producing, from rubber waste, a resilientsole simply and rapidly, at a low cost, by making it possible to meetthe requirements of each actor of the market. The sole is made from twolayers, without any bonding between them.

Devulcanised rubber, which is a recycled rubber, is obtained bydevulcanisation. This devulcanisation can be done at the start ofmanufacturing the resilient sole or it can be done upstream ofmanufacturing said resilient sole.

More specifically, this devulcanised rubber is a devulcanised rubber,reactivated by adding at least one additive.

The layer of structured fibres is, by superposition, brought intocontact with said devulcanised rubber layer, before pressing. This stepmakes it possible to obtain two superposed layers.

The two superposed layers are brought to a press and the hot-pressed ata temperature of between 100 and 180° C., preferably between 140 and170° C., preferably between 150 and 160° C. during a predetermined timeinterval. This hot pressing will thus enable the revulcanisation of thedevulcanised rubber layer and, during this revulcanisation, an at leastpartial impregnation of the structured fibres of the layer of structuredfibres in the rubber layer thus forming a revulcanised rubber-fibreinterphase. Thus, during hot pressing, the rubber is revulcanised in thethickness of the rubber layer, but also around structured fibres. Thestructured fibres have a melting point greater than the hot pressingtemperature.

According to the present invention, the pressing is the result of theforce necessary to compress the rubber. The hot pressing can be carriedout by any device known for this purpose, in particular in a mould oralso between two pressing strips. The pressing strips are adjusted to alayer thickness between 10 and 25% less than the thickness of the twosuperposed layers.

According to the present invention, by the term “revulcanised rubber”,this means that the rubber is a rubber wherein sulphur bonds arerecreated during hot pressing.

By the term “reactivated devulcanised rubber”, this means according tothe present invention, a rubber of which the reactivation of sulphurbonds is ready to be triggered.

According to the present invention, by the term “partial impregnation ofstructured fibres”, this means that the layer of structured fibres has,at the end of the method, a free thickness of structured fibres, i.e.non-impregnated in the revulcanised rubber and a thickness of structuredfibres impregnated in the revulcanised rubber.

The method for manufacturing a resilient sole according to the presentinvention has the advantage or providing a resistant, robust and qualitysole.

During devulcanisation, it is advantageous that the viscosity of thedevulcanised rubber is less than 70 MU, preferably less than 50 MU, morespecifically less than 40 MU, measured on a Mooney viscometer. Thisviscosity will favour the formation of a revulcanised rubber-fibreinterphase by the at least partial impregnation of the fibres of thefibrous structure in the rubber layer obtained during hot pressing. Itis preferable, but not excluded, that there is no total impregnation ofthe fibres during the compression step.

In addition, this viscosity will make it possible to produce variedresilient soles which will be able to meet the expectations of each ofthe actors of the targeted market. Indeed, the manufacturing methodmakes it possible to obtain resilient soles in a wide range of solerigidities.

In addition, the method for manufacturing a resilient sole according tothe present invention has the advantage of being achieved at a low costby using a rubber coming from the recycling process and a layer ofstructured fibres, the basic features of which make it possible toobtain it at a low cost. It therefore enables a circular economy byusing company waste to give them a new life in another technical field.

The dependent claims refer to other advantageous embodiments.

In a preferred embodiment, the additive(s) used in the addition stepcomprise sulphur and/or at least one resin and/or at least one reactionactivator or accelerator and/or carbon black.

Advantageously, said at least one resin according to the presentinvention is a thermoplastic resin chosen from the group comprisingresins having at least one phenol group, at least one aromatic group, atleast one styrene group, or any other resin which could be used withsulphur-vulcanised rubber or their combination.

Preferably, said at least one reaction activator or acceleratoraccording to the present invention is chosen from the group comprisingCBS, stearic acid, zinc oxide.

Advantageously, said predetermined time interval of the hot pressingstep of the method for manufacturing the sole according to the presentinvention is between 3 and 12 minutes, preferably between 4 and 10minutes, more specifically, between 5 and 6 minutes.

According to an advantageous embodiment of the invention, after theaddition of at least one abovesaid additive, the devulcanised recycledrubber mass is shaped and the layer of structured fibres and thedevulcanised recycled rubber, shaped, are superposed so as to form saidtwo layers.

It can occur, in certain cases, a total impregnation of the fibres inthe rubber layer during revulcanisation, during hot pressing. In thiscase, the method further comprises a brushing on the surface of theimpregnated structured fibres, so as to make these partially free, on apredetermined thickness.

Other embodiments of the method for manufacturing a resilient soleaccording to the invention are indicated in the accompanying claims.

Other features, details and advantages of the invention will emerge fromthe description given below, in a non-limiting manner, and by makingreference to the drawings and to the examples.

FIG. 1 is a cross-sectional view of a resilient sole according to thepresent invention.

FIG. 2 is a cross-sectional view of an assembly comprising a concretelayer arranged to be used as a rail and a resilient sole according tothe present invention.

FIGS. 3 to 6 illustrate a method for manufacturing a resilient soleaccording to the invention.

FIG. 7 illustrates a superficial brushing step after hot pressing,according to a particular embodiment of the manufacturing methodaccording to the invention.

In the figures, the identical or similar elements have the samereferences.

FIG. 1 illustrates a resilient sole 1 according to the inventionarranged to be positioned between a concrete block (not represented) anda ballast (not represented). This resilient sole 1 comprises:

-   -   a revulcanised rubber layer 4,    -   a layer of structured fibres 5 partially impregnated in the        revulcanised rubber layer 4,    -   an interphase 6 comprising impregnated structured fibres 7 and        revulcanised rubber 4.

According to the present invention, by the term “partially impregnatedin the revulcanised rubber layer 4”, this means that the layer ofstructured fibres 5 has a free thickness 8 of structured fibres, i.e.not impregnated in the revulcanised rubber layer, and a thickness 7 ofimpregnated structured fibres in the revulcanised rubber 4.

To obtain this resilient sole 1, a devulcanised rubber sample is taken,coming from tyre waste of different vehicles. After having added atleast one additive intended to reactive the devulcanised rubber to thissample, it has been shaped in the form of a strip. Said devulcanisedrubber strip is positioned on a lower conveyor belt.

Then, a layer of structured fibres 5 is superposed on the devulcanisedrubber layer and two superposed layers are obtained.

Said two superposed layers a conveyed to a press. Said two superposedlayers are pressed at a temperature of 120° C. for 5 minutes. The rubberhas thus been revulcanised during pressing and a resilient sole 1 isobtained according to the present invention. During hot pressing, thestructured fibres have been partially impregnated in said revulcanisedrubber layer 4 by forming the revulcanised rubber-fibre interphase 6.

FIG. 2 illustrates an assembly 10 comprising a concrete layer 2 arrangedto be used as a rail and a resilient sole 1 according to the presentinvention, assembly wherein said structured fibres 5 are furtherpartially impregnated, on the free thickness 8 of structured fibres, insaid concrete layer 2, and this before taking the concrete.

The rail, formed from the concrete layer 2 and equipped with a resilientsole 1 according to the invention, for the dissipation of vibrations,can thus be placed on a ballast 3.

In FIGS. 3 to 6 , a resilient sole according to the invention ismanufactured according to another embodiment of the invention.

After devulcanisation, the recycled, devulcanised rubber mass, is mixedwith additives which promote the mainly mechanical features of the sole.In particular, carbon black which modifies the hardness, the stiffnessand the dissipative power of the vibrations of the obtained sole can beadded. The activators/accelerators enable an activation or accelerationof the reactivity of the rubber and therefore of its revulcanisation,which will also determine the cross-linking density of the sole.

The devulcanised mass is, after adding the abovementioned additives,shaped, in particular in the form of a plate 11 having the dimensions ofa mould 12. Likewise, a thermoplastic, preferably polypropylene feltlayer 13, is cut to the size of the mould.

The mould 12 is preheated to a temperature less than the melting pointof the fibres of the felt, preferably between 140 and 170° C.,advantageously between 150 and 160° C.

In the preheated mould, first the cut felt 13 is introduced, then thedevulcanised, shaped rubber plate 11 is superposed there.Advantageously, the height of the felt assembly 13 and rubber plate 11is greater than the depth of the cavity of the mould 12. Then, the cover14 of the mould 12 is closed, as represented in FIG. 4 , and theassembly is hot compressed at a pressure preferably greater than 2 MPa,advantageously 6 MPa. This pressure must be sufficient to discharge theexcess material 15 outside of the mould, as represented in FIG. 5 .

The vulcanisation time depends on the activation/acceleration of thedevulcanised rubber mass used. This time can vary between 2 and 15minutes, advantageously between 3 and 7 minutes.

Thus, the mould can be opened, the non-compressed excess materialremoved, and the resilient sole illustrated in FIG. 6 extracted from themould, which has

-   -   a revulcanised rubber layer 9,    -   a layer of structured fibres 13 partially impregnated in the        revulcanised rubber layer 9, and    -   an impregnated felt fibre-revulcanised rubber interphase 16.

In certain cases, in particular when the devulcanised rubber is of lowviscosity and/or the felt of low density, the fibres of the felt aretotally buried in the rubber layer after the hot pressing step, byforming a layer of totally impregnated fibres 20 in the revulcanisedrubber layer 9. A superficial brushing of the layer of impregnatedfibres 20 is thus necessary to release some of the fibres on apredetermined thickness. This brushing can be done as represented inFIG. 7 , using a circular brush 17 mounted on an axis and adjusted to apredetermined height of a conveyor belt 18. The passage under this brushof the resilient sole exiting from the mould will thus clear a freethickness 19 of structured fibres, which may enable the subsequentfastening of a concrete layer.

It is well understood that the present invention is not, in any way,limited to the embodiments described above and that plenty ofmodifications can be applied to it, without moving away from the scopeof the accompanying claims.

1. A resilient sole, arranged in particular to be attached to a concretelayer or positioned between a concrete layer and a ballast, comprising:a recycled rubber layer, in the revulcanised state afterdevulcanisation, and a layer of structured fibres, arranged in contactwith the rubber layer, said fibres being partially impregnated in saidrubber layer and having a free thickness of structured fibres.
 2. Theresilient sole according to claim 1, wherein the structured fibres havea density of between 150 g/m² and 800 g/m².
 3. The resilient soleaccording to claim 1, wherein the fibres are impregnated at a depth ofbetween 0.5 and 2 mm, in the revulcanised state.
 4. The resilient soleaccording to claim 1, wherein said recycled rubber layer in therevulcanised state has a Shore hardness of between 50 and 90, accordingto the standard measuring model, the durometer.
 5. The resilient soleaccording to claim 1, wherein said fibres are chosen from the group ofnatural or synthetic materials, like polyester, polypropylene,polystyrene, polyethylene, wool, cotton, hemp, coconut fibres.
 6. Theresilient sole according to claim 1, wherein said recycled rubber layercomprises the rubber chosen from the group of natural or syntheticmaterials, like natural polyisoprene, isoprene polymer, polybutadiene,styrene-butadiene copolymer.
 7. The resilient sole according to claim 1,wherein said rubber layer has a resistance to traction greater than orequal to 7 MPa.
 8. The resilient sole according to claim 1, wherein saidrubber layer has an extension to rupture greater than 150%.
 9. Anassembly, comprising: a concrete layer; and a resilient sole, comprisinga recycled rubber layer, in the revulcanised state afterdevulcanisation, and a layer of structured fibres, arranged in contactwith the rubber layer, said fibres being partially impregnated in saidrubber layer and having a free thickness of structured fibres, whereinsaid structured fibres are further partially impregnated on the freethickness of structured fibres in said concrete layer.
 10. The assemblyaccording to claim 9, wherein said fibres are impregnated in theconcrete block on a thickness of between 0.3 and 2 mm.
 11. A method formanufacturing a resilient sole comprising: devulcanising recycledrubber, including formation of a devulcanised recycled rubber mass,adding at least one devulcanised recycled rubber additive,superpositioning a layer of structured fibres and devulcanised recycledrubber, including obtaining of two superposed layers, hot pressing saidtwo superposed layers at a temperature of between 100 and 180° C. duringa predetermined time interval with revulcanisation of the devulcanisedrecycled rubber and formation of a resilient sole where the structuredfibres are at least partially impregnated in said rubber layer duringrevulcanisation, by forming a revulcanised rubber-fibre interphase. 12.The method for manufacturing a resilient sole according to claim 11,wherein said at least one additive comprises sulphur, or at least oneresin, or at least one reaction activator or accelerator, or carbonblack.
 13. The method for manufacturing a resilient sole according toclaim 12, wherein said at least one resin is a resin chosen from thegroup comprising resins having at least one phenol group, at least onearomatic group, at least one styrene group, and any other resin whichcould be used with sulphur-vulcanised rubber and their combination. 14.The method for manufacturing a resilient sole according to claim 12,wherein said at least one reaction activator is chosen from the groupcomprising CBS, stearic acid and zinc oxide.
 15. The method formanufacturing a resilient sole according to claim 11, wherein after theaddition of at least one abovesaid additive, the devulcanised recycledrubber mass is shaped and in that the layer of structured fibres and thedevulcanised, shaped recycled rubber, are superposed so as to form saidtwo layers.
 16. The method for manufacturing a resilient sole accordingto claim 11, wherein during the hot pressing, the structured fibres aretotally impregnated in said rubber layer during revulcanisation, themethod further comprising superficially brushing the impregnatedstructured fibres, so as to make these partially free, on apredetermined thickness.
 17. The method for manufacturing a resilientsole according to claim 11, wherein the superposition and hot pressingsteps are carried out in a mould.
 18. The method for manufacturing aresilient sole according to claim 11, wherein said devulcanised recycledrubber has a viscosity less than 70 MU, measured on a Mooney viscometer.